Digu Pi San: Treating Deficiency Heat, Dry Mouth and Insomnia

In the Taiping Shenghuifang there is a formula called “Digu Pi San.” It is composed of: Digu Pi (Lycium root bark) two liang (60 g), Tianhuafen (Trichosanthes root) one liang (30 g), Shigao (Gypsum) one liang (30 g), Huanglian (Coptis) one liang (30 g), Zhi Gancao (honey-fried Licorice) one liang (30 g). Preparation: make the above into a coarse powder. Each dose: take 4 qian (12 g), boil with one zhan (about 200 ml) of water down to six-tenths (about 120 ml), strain, and take warm while hot.

Nowadays Chinese herbal slices are usually decocted directly. If using slices, the adult daily dose is: Digu Pi 12 g, Tianhuafen 6 g, Sheng Shigao (raw Gypsum, decocted first for 10 minutes) 6 g, Huanglian 6 g, Zhi Gancao 6 g; decoct in water, one dose daily, taken morning and evening. Huanglian in this formula is very bitter; if taken long term, consider making it into pills, taking 3–6 g of pills each time, 2–3 times daily.

This formula clears the stomach and engenders fluids. It treats “middle-xiao” among the “three-xiao” (three types of wasting-thirst), presenting with an emaciated body, deficiency heat, dry mouth and restless sleep. “Middle-xiao” is a TCM disease name, also called “xiao-zhong,” referring to wasting-thirst whose main manifestations are a good appetite with much eating and emaciation. The Zhengzhi Yaojue states: “Xiao-pi arises because the spleen channel is dry and hot; food is quickly transformed and all passes into the urine, and the more one eats, the hungrier one becomes." Volume 53 of the Taiping Shenghuifang states: “The three xiao are: the first is xiao-ke (thirst-wasting), the second xiao-zhong, the third xiao-shen. The first, where much water is drunk but little urine is passed, is xiao-ke. The second, where much food is eaten but little water drunk, with little yellowish-red urine, is xiao-zhong. The third, where drunk water immediately passes out, with sweet, cloudy-white urine and wasting of the waist and legs, is xiao-shen.”

In TCM view, “middle-xiao” is mostly caused by stomach fire, so treatment should mainly use heat-clearing, thirst-stopping herbs. Digu Pi, Tianhuafen, Shigao and Huanglian used here all belong to this category. From the actions of these herbs, we may roughly infer that Digu Pi San mainly treats deficiency heat, dry mouth and insomnia caused by chronic stomach disease, hyperthyroidism or diabetes. It can also be used for cancer patients with dry mouth and parched throat, profuse sweating and sleeplessness caused by radiotherapy, and for advanced cancer patients with deficiency heat, dry mouth and insomnia due to tumor fever.

This formula heavily uses Digu Pi, the root of the Gouqi (Lycium) plant. It has antipyretic and analgesic actions, raises leukocytes, lowers blood pressure, blood lipids and cholesterol, and has antibacterial effects. TCM holds that Digu Pi recedes deficiency heat, cools blood and stops bleeding; it excels at clearing lung and stomach fire, engendering fluids and stopping thirst. It is commonly used for yin-deficiency fever, steaming bone fever with sweating, deficiency-fire toothache, infantile gan-heat, blood-heat vomiting of blood, nosebleed and hematuria, lung-heat cough, and internal-heat wasting-thirst. Digu Pi may cause diarrhea; those with spleen deficiency and loose stools should use it cautiously.

Tianhuafen is the rhizome of Gualou (Trichosanthes). It clears heat and engenders fluids, clears the lung and moistens dryness, disperses swelling and discharges pus. It is mainly used for thirst from heat damage to fluids, internal-heat wasting-thirst, lung-heat cough, dry cough with sticky phlegm, or blood-tinged sputum. Tianhuafen lowers blood sugar, and has antibacterial, antiviral, anti-early-pregnancy and anti-tumor actions; but it may cause diarrhea, so those with spleen deficiency and loose stools should use it cautiously.

Raw Shigao clears heat and drains fire, eliminates restlessness and stops thirst; it is commonly used for high heat in the qi portion in warm diseases, lung-heat cough and panting, stomach-fire headache, gum swelling and pain, and mouth and tongue sores. Calcined Shigao astringes and engenders flesh. Given the treatment aim of this formula, the Shigao here should be raw Gypsum. Raw Shigao has antipyretic, antispasmodic and anti-inflammatory actions and can enhance phagocytic activity, but it is greatly cold in nature; those with spleen deficiency should use it cautiously.

Huanglian clears heat and dries dampness, drains fire and resolves toxin. It is commonly used for damp-heat obstruction and fullness with vomiting, diarrhea and dysentery, jaundice, high fever in heat diseases, restlessness with coma, internal heat with vexed insomnia, stomach-fire toothache, mouth and tongue sores, liver fire invading the stomach with vomiting and acid regurgitation, blood-heat vomiting and nosebleed, sores and abscesses, red swollen painful eyes, furuncles in the ear canal, and damp-heat sores. Berberine (huangliansu), the active component extracted from Coptis, is a broad-spectrum antiviral, antibacterial and anti-inflammatory medicine now commonly used for acute gastroenteritis. Huanglian inhibits many pathogenic bacteria and viruses, and also has antiarrhythmic, antihypertensive, ischemic-myocardium-protective, blood-sugar-lowering, brain-injury-protective, antipyretic, analgesic, anticonvulsant and anti-tumor actions; its uses are very broad.

The four herbs above are all bitter-cold, and readily injure the spleen and stomach; they must be combined with a mild sweet herb like Zhi Gancao to reduce side effects, and Zhi Gancao also engenders fluids and stops thirst. Overall, this is a formula that clears and drains stomach fire, nourishes yin and moistens dryness, and so can treat the deficiency heat, dry mouth and insomnia caused by middle-xiao.